474
Velocity.
I!'?!
With an original velocity v the distance is found by adding the
two areas at r>, Fig 434. (See p. 1099.)
A
4\secs.
M"23
C sec^-
Uniformly Retarded Velocity is a similar case to D, the
final velocity and total distance being found by subtraction of
areas, as at E, and are vl - v2 and sl - ^respectively.
Collating results, with ^ as original and z>2 as final velocities,
U.A.V. from rest.
U.A.V. with original velocity.
U.R.V.
v^ft
J&-^+/'
^2 = *'l //
s = J//»
>'='/#! +' ^//2
*=/*!- i//a
V* = 2/S
V<? = ^2 + 2/V
^22= »!2 2/J
Example 4p. A locomotive and train weighing 100 tons start on
a level, and attain a speed of 60 miles per hour within one minute.
What was the mean pull exerted ?
^ , x -
From ft) / - 7 -
and Pull in Ibs. - =
Io° x
22
- . IO266 Ibs.
32 x 15
or 4-6 tons, neglecting friction. ,
Conservation of Momentum; Two balls, A and B,
Fig. 435, raised simultaneously, are allowed to fall, strike, and
rebound. The duration of shock is called the impact, and it is